The condition of a civilian who suffered serious burns as the fire spread out of control Wednesday could not be confirmed.

Jeff Larusso with the Riverside County Fire Department did not identify the victim or elaborate on the extent of injuries, saying only that they occurred "early on" in the fire. The burn victim was airlifted to Arrowhead Regional Medical Center in Colton, he added.

The Silver fire broke out around 2 p.m. Wednesday and soon exploded into an uncontrolled blaze that moved quickly around Banning, sending more than 1,500 residents in mandatory evacuation zones fleeing.

Some of them were forced to "shelter in place" after the fire cut off exit paths.

Berlant said fire incident commanders would continue to monitor the movement of the blaze to determine if more evacuation orders should be given.

Meanwhile, officials said they were focusing firefighting efforts -- including a heavy air attack -- on keeping the fire line away from more dense forest areas where there would be more fuel to burn.

"Basically, our priority today is keeping [the fire] off San Bernardino National Forest," Larusso said. "As of right now, we're not into the heavy dense fuels, we're not seeing the type of timber fuels that burn hotter."